Synthesis and characterization of Cu-Zn/TiO 2 for the photocatalytic conversion of CO 2 to methane


​Different Cu-Zn/TiO2 catalysts were synthesized by using wet impregnation method. The prepared catalysts were employed for the conversion of CO2 into methane by photocatalysis. Various characterization techniques were used to observe the surface morphology, crystalline phase, BET surface area, presence of impregnated Cu and Zn, and functional group. SEM analysis showed the spherical morphology and slight agglomeration of catalyst particles was obsevered. BET analysis revealed that the surface area of the catalsyt was decreased from 10 to 8.5 m(2)/g after impregnation of Cu and Zn over TiO2 support. Synergetic effect of Cu and Zn over TiO2 support (Cu2.6/TiO2, Zn0.5/TiO2 and Cu2.6-Zn0.5/TiO2) and the effects of Cu loading (0, 1.8, 2.1, 2.6 and 2.9 wt%) were also investigated at different feed molar ratios of H2/CO2 (2:1 and 4:1). Cu2.6-Zn0.5/TiO2 catalyst showed a maximum conversion of 14.3% at feed molar ratio 4. Addition of Zn over catalyst surface has increased the conversion of CO2 from 10 to 14.3% that might be due to synergy of Cu and Zn over TiO2 support.